A cloud storage system may store an object and replicas thereof in a plurality of data nodes in response to a user request. The object may be any type of data. For example, the object may be document files and multimedia files. The document files may include Microsoft (MS) word documents or Portable Document Format (PDF) files. The multimedia files may include audio files for songs and image files for still and/or motion pictures. The present invention, however, is not limited thereto.
For many purposes, such as high reliability and availability, a cloud storage system may create replicas of the object and distributedly store the replicas in a plurality of data nodes. In order to effectively store the object and the replicas thereof, a cloud storage system may refer to multiple cloud storage policies to select areas and data nodes for storing the object and the replicas thereof. The cloud storage policies may define storage locations and rules for storing the object and the replicas. The cloud storage polices may include an area diversity policy, and a locality policy.